Rapid modulation of transcription of nuclear genes encoding chloroplast proteins by light

Abstract We have investigated the effects of light on transcription of the nuclear genes encoding the small subunit (SSU) of ribulose-1,5-biphosphate carboxylase-oxygenase, and the major apoprotein (LHCP) of the lightharvesting chlorophyll a / b complex in Pisumsativum . Light treatments were given in vivo and transcription was assayed subsequently in isolated nuclei using specific cloned cDNA probes. We have identified three different temporal effects of light on transcription of these genes: an initial increase when dark-grown seedlings are first illuminated, a slow increase in the ability to transcribe these genes at maximal rates, and a rapid modulation of specific gene transcription in fully greened plants.